The present invention relates to methods for preparing xcex2-ketoester fragrance pro-accords, said pro-accords useful for providing sustained fragrance to items which deliver perfume for aesthetic reasons inter alia laundry detergent compositions, fabric softeners, personal care and personal hygiene items, shampoos, body lotions, and fabric re-fresheners. The process of the present invention relates to the use of 1,3-dioxane-4,6-diones as a synthon for the facile formation of xcex2-ketoesters, especially xcex2-ketoesters which comprise a tertiary alcohol subunit.
Esters which release perfume alcohols are currently of interest for their different odor profiles in products, as well as their odor profiles during and after use. Particularly desirable are such esters which have a prolonged release characteristic from use in a home laundering process. Deposition onto a substrate, for example, onto fabric during the wash process followed by delayed release of the perfume after drying, is especially desirable. The challenge for using such esters include not only the right combination of storage stability and odor release profile, but also the challenge of making such esters in a cost effective manner.
xcex2-Ketoesters are a particularly desirable class of materials, but such materials can present a particular challenge for a cost effective production. The di-functionality (ketone and carboxylic ester functionality in the same compound) of these compounds limits the types of reactions and conditions under which these compounds can be made. Add on the industrial scale and cost constraints that the use of specialty reactants add to the possible synthesis methods, and the large scale of production of such xcex2-ketoester compounds for use in high volume consumer products becomes problematic.
Accordingly there remains a need in the art for a method for a simple, high yield, cost-effective means for preparing xcex2-ketoester fragrance pro-accords. In addition there is a need for convenient methods which produce xcex2-ketoesters capable of releasing tertiary alcohols inter alia dihydromyrcenol and linalool.
The following relate to the preparation of xcex2-ketoesters from 1,3-dioxane-4,6-diones. Oikawa et al., J. Org. Chem., Vol 43, No 10, 1978, pg. 2087; Capozzi et al., J. Org. Chem., Vol 58, No 27, 1993, pg. 7932; Organic Synthesis Collective Volumes, pg 359, Oikawa et al., submitters; and Houghton et al., xe2x80x9cA Modified Preparation of xcex2-Keto Estersxe2x80x9d, Synthesis, pg 451, (1982).
It has now been surprisingly discovered that molecules which releasably comprise fragrance raw material alcohols, namely xcex2-ketoester fragrance pro-accords, can be suitably prepared from activated acyl adducts, for example, acid chlorides, and 1,3-dioxan-4,6-diones followed by reacting the product with a fragrance raw material alcohol. It is especially desirable that the fragrance raw material alcohols which become a subunit of the xcex2-ketoester fragrance pro-accord are tertiary alcohols, for example, linalool and dihydromycenol.
The first aspect of the present invention relates to a process for preparing xcex2-ketoester fragrance pro-accords comprising the steps of:
a) reacting in the presence of a base a 1,3-dioxane-4,6-dione having the formula: 
wherein R1 and R2 are each independently C1-C10 alkyl, C2-C10 alkenyl, C7-C22 alkylenearyl, C6-C10 aryl, and mixtures thereof; with an activated acyl group having the formula: 
wherein R3, R4, and R5 are each independently hydrogen, C1-C30 substituted or unsubstituted linear alkyl, C3-C30 substituted or unsubstituted branched alkyl, C3-C30 substituted or unsubstituted cyclic alkyl, C1-C30 substituted or unsubstituted linear alkoxy, C3-C30 substituted or unsubstituted branched alkoxy, C3-C30 substituted or unsubstituted cyclic alkoxy, C2-C30 substituted or unsubstituted linear alkenyl, C3-C30 substituted or unsubstituted branched alkenyl, C3-C30 substituted or unsubstituted cyclic alkenyl, C2-C30 substituted or unsubstituted linear alkynyl, C3-C30 substituted or unsubstituted branched alkynyl, C6-C30 substituted or unsubstituted alkylenearyl; or R3, R4, and R5 can be taken together to form C6-C30 substituted or unsubstituted aryl; and mixtures thereof; X is an acyl activating unit; to form an acyl 1,3-dioxane-4,6-dione, the enol tautomer of which having the formula: 
b) optionally, isolating said acyl 1,3-dioxane-4,6-dione; and
c) reacting said acyl 1,3-dioxane-4,6-dione from step (a) or (b) with a fragrance raw material alcohol having the formula:
ROH
to form a xcex2-ketoester fragrance pro-accord having the formula: 
wherein R3, R4, and R5 are the same as defined herein above.
The present invention more specifically relates to the preparation of xcex2-ketoester fragrance pro-accords which comprise a secondary or tertiary alcohol subunit, more preferably a tertiary alcohol subunit. These and other objects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims.
All percentages, ratios and proportions herein are by weight, unless otherwise specified. All temperatures are in degrees Celsius (xc2x0 C.) unless otherwise specified. All documents cited are in relevant part, incorporated herein by reference.
The present invention relates to a process for preparing xcex2-ketoester fragrance pro-accords from 1,3-dioxan-4,6-diones, preferably from 2,2-dimethyl-1,3-dioxan-4,6-dione. Variations of the present process include isolation and purification of the intermediate acyl 1,3-dioxane-4,6-dione formed in Step (a) prior to subsequent reaction with a fragrance raw material alcohol. However, the formulator, depending upon several variables inter alia the structure of the final xcex2-ketoester, the amount of material to be produced, the type of process (i.e. batch reactions vs. continuous process) may produce the final product without isolation of the acyl 1,3-dioxan-4,6-dione intermediate.
For the purposes of the present invention the term xe2x80x9csubstitutedxe2x80x9d as it applies to linear alkyl, branched alkyl, cyclic alkyl, linear alkenyl, branched alkenyl, cyclic alkenyl, branched alkoxy, cyclic alkoxy, alkynyl, and branched alkynyl units are defined as xe2x80x9ccarbon chains which comprise substitutents other than branching of the carbon atom chainxe2x80x9d, for example, other than the branching of alkyl units (e.g. isopropyl, isobutyl). Non-limiting examples of xe2x80x9csubstituentsxe2x80x9d include hydroxy, C1-C12 alkoxy, preferably methoxy; C3-C12 branched alkoxy, preferably isopropoxy; C3-C12 cyclic alkoxy; nitrilo; halogen, preferably chloro and bromo, more preferably chloro; nitro; morpholino; cyano; carboxyl, non-limiting examples of which are xe2x80x94CHO; xe2x80x94CO2xe2x88x92M+, xe2x80x94CO2R9; xe2x80x94CONH2; xe2x80x94CONHR9; xe2x80x94CONR92; wherein R9 is C1-C12 linear or branched alkyl); xe2x80x94SO3xe2x88x92M+; xe2x80x94OSO3xe2x88x92M+; xe2x80x94N(R10)2; and xe2x80x94N+(R10)3Xxe2x88x92 wherein each R10 is independently hydrogen or C1-C4 alkyl; and mixtures thereof; wherein M is hydrogen or a water soluble cation; and X is chlorine, bromine, iodine, or other water soluble anion.
For the purposes of the present invention substituted or unsubstituted alkyleneoxy units are defined as moieties having the formula: 
wherein R7 is hydrogen; R8 is hydrogen, methyl, ethyl, and mixtures thereof; the index x is from 1 to about 10.
For the purposes of the present invention substituted or unsubstituted alkyleneoxyalkyl are defined as moieties having the formula: 
wherein R7 is hydrogen, C1-C18 alkyl, C1-C4 alkoxy, and mixtures thereof; R8 is hydrogen, methyl, ethyl, and mixtures thereof; the index x is from 1 to about 10 and the index y is from 2 to about 18.
For the purposes of the present invention substituted or unsubstituted aryl units are defined as phenyl moieties having the formula: 
or xcex1 and xcex2-naphthyl moieties having the formula: 
wherein R7 and R8 can be substituted on either ring, alone or in combination, and R7 and R8 are each independently hydrogen, hydroxy, C1-C6 alkyl, C2-C6 alkenyl, C1-C4 alkoxy, C3-C6 branched alkoxy, nitrilo, halogen, nitro, morpholino, cyano, carboxyl (xe2x80x94CHO; xe2x80x94CO2xe2x88x92M+; xe2x80x94CO2R9; xe2x80x94CONH2; xe2x80x94CONHR9; xe2x80x94CONR92; wherein R9 is C1-C12 linear or branched alkyl), xe2x80x94SO3xe2x88x92M+, xe2x80x94N(R10)2, and xe2x80x94N+(R10)3Xxe2x88x92 wherein each R10 is independently hydrogen, C1-C4 alkyl or mixtures thereof; and mixtures thereof, R7 and R8 are preferably hydrogen, C1-C6 alkyl, xe2x80x94CO2xe2x88x92M+, xe2x80x94SO3xe2x88x92M+, xe2x80x94OSO3xe2x88x92M+, and mixtures thereof; more preferably R7 or R8 is hydrogen and the other moiety is C1-C6; wherein M is hydrogen or a water soluble cation and X is chlorine, bromine, iodine, or other water soluble anion. Examples of other water soluble anions include organic species such as fumarate, succinate, tartrate, oxalate and the like, inorganic species include sulfate, hydrogen sulfate, phosphate and the like.
For the purposes of the present invention substituted or unsubstituted alkylenearyl units are defined as moieties having the formula: 
wherein R7 and R8 are each independently hydrogen, hydroxy, C1-C4 alkoxy, nitrilo, halogen, nitro, carboxyl (xe2x80x94CHO; xe2x80x94CO2xe2x88x92M+; xe2x80x94CO2R9; xe2x80x94CONH2; xe2x80x94CONHR9; xe2x80x94CONR92; wherein R9 is C1-C12 linear or branched alkyl), amino, alkylamino, and mixtures thereof, p is from 1 to about 14; M is hydrogen or a water soluble cation.
For the purposes of the present invention substituted or unsubstituted alkyleneoxyaryl units are defined as moieties having the formula: 
wherein R7 and R8 are each independently hydrogen, hydroxy, C1-C4 alkoxy, nitrilo, halogen, nitro, carboxyl (xe2x80x94CHO; xe2x80x94CO2xe2x88x92M+; xe2x80x94CO2R9; xe2x80x94CONH2; xe2x80x94CONHR9; xe2x80x94CONR92; wherein R9 is C1-C12 linear or branched alkyl), amino, alkylamino, and mixtures thereof, q is from 1 to about 14; M is hydrogen or a water soluble cation.
The following summarizes the process of the present invention.
Step (a) Formation of a 2-acyl-1,3-dioxan-4,6-dione
The first step of the process of the present invention relates to reacting an activated acyl moiety of the general formula: 
with a 1,3-dioxan-4,6-dione having the formula: 
to form a 2-acyl-1,3-dioxan-4,6-dione having, in its enol tautomer form, the formula: 
wherein R1 and R2 are each independently C1-C10 alkyl, C2-C10 alkenyl, C7-C22 alkylenearyl, C6-C10 aryl, and mixtures thereof, preferably methyl; wherein R3, R4, and R5 are each independently hydrogen, C1-C30 substituted or unsubstituted linear alkyl, C3-C30 substituted or unsubstituted branched alkyl, C3-C30 substituted or unsubstituted cyclic alkyl, C1xe2x80x94C30 substituted or unsubstituted linear alkoxy, C3-C30 substituted or unsubstituted branched alkoxy, C3-C30 substituted or unsubstituted cyclic alkoxy, C2-C30 substituted or unsubstituted linear alkenyl, C3-C30 substituted or unsubstituted branched alkenyl, C3-C30 substituted or unsubstituted cyclic alkenyl, C2-C30 substituted or unsubstituted linear alkynyl, C3-C30 substituted or unsubstituted branched alkynyl, C6-C30 substituted or unsubstituted alkylenearyl; or R3, R4, and R5 can be taken together to form C6-C30 substituted or unsubstituted aryl; and mixtures thereof; preferably two of R3, R4, and R5 are hydrogen and the remaining group is C1-C10 linear or branched alkyl, C2-C10 linear or branched alkenyl, preferably methyl and octyl, also preferably R3, R4, and R5 are taken together to form a substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, more preferably naphthyl.
X is an acyl activating unit. Non limiting examples of acyl activating units are acyloxy units having the formula xe2x80x94OC(O)Rxe2x80x2 which when taken together with the acyl moiety form a symmetrical or non-symmetrical anhydride, wherein Rxe2x80x2 is the same or different than the moiety which is formed by R3, R4, and R5. However, in cases where anhydride-like conditions are desired and formation of the acyl unit anhydride is either impractical or unobtainable, then the acyl carboxylic acid may be condensed with the 1,3-dioxan-4,6-dione in the presence of a condensing agent such as ethyl phosphonocyanidate. Other non-limiting examples of activated acyl units are acyl acid halides wherein X is chlorine, bromine, iodine, and mixtures thereof, activated esters, for example, 4-nitrophenyl esters of the acyl unit defined by R3, R4, and R5.
The reaction of Step (a) of the present process is conducted in the presence of a base suitable to de-protonate the 2-position carbon of the selected 1,3-dioxan-4,6-dione. The acidity of the protons on the 2-carbon of the 1,3-dioxan-4,6-dione, and therefore the strength of the base necessary for reaction of Step (a), is governed by a number of factors, notably the structure of the dione itself. Bases suitable for use are selected from the group consisting of alkylamines, aromatic amines, polymeric amines, organo lithium compounds, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, alkaline earth metal carbonate, alkali metal hydrides, alkaline earth metal hydrides, and mixtures thereof.
Non-limiting examples of bases suitable for use in the present invention are aromatic amines, for example, pyridine, picoline, lutidine, collidine; mono-, di-, and tri-alkylamines, for example, methyl amine, trimethylamine, triethanolamine; alkali metal and alkaline earth metal hydrides, for example, lithium hydride, sodium hydride; alkali metal alkoxides, for example, sodium ethoxide, sodium methoxide; alkali metal and alkaline earth metal carbonates and bicarbonates, for example sodium carbonate, potassium carbonate; organo metallic compounds, for example, butyl lithium, t-butyl lithium; alkali metal and alkaline earth metal hydroxides, for example, sodium hydroxide, potassium hydroxide. Preferred bases are pyridine and sodium hydride.
Depending upon the reaction conditions desired by the formulator, Step (a) can be conducted in the presence of a suitable solvent. Non-limiting examples of suitable solvents include dichloromethane, 1,2-dichloroethane, 1,2,3-trichloroethane, pentane, hexane, tetrahydrofuran, diethyl ether, benzene, toluene, xylene, 1,4-dioxane, acetonitrile, and mixtures thereof. In addition, the formulator may wish to adjust the reaction conditions to stabilize the formation of charged reaction species in which the use of solvents such as N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), hexamethyl phosphoramide (HMPA), and the like may be used alone or in combination with other suitable solvents. However, the formulator may generate the 1,3-dioxan-4,6-dione anion in water followed by isolation of the 1,3-dioxan-4,6-dione salt typically followed by thorough drying.
The reaction of Step (a) may be successfully conducted, depending upon the reactivity of the reagents, the scope of the reaction, and other mitigating parameters, at a temperature of from about xe2x88x9270xc2x0 C., preferably from about xe2x88x9233xc2x0 C., more preferably from about 0xc2x0 C., most preferably from about 22xc2x0 C.(approximately room temperature), to about 100xc2x0 C., preferably to about 80xc2x0 C., more preferably to about 60xc2x0 C., most preferably to about 40xc2x0 C. The reaction of Step (a) may be conducted at more than one temperature, for example, during the addition of reagents the temperature of the reaction may be held at a first temperature, for example 0xc2x0 C., and allowed to warm to a second temperature after the addition is complete. Alternatively, the reaction may be warmed to generate the 1,3-dioxane-4,6-dione anion, then cooled during the addition of the activated acyl adduct.
The reaction of Step (a) may be conducted in any order which insures formation of the desired acyl 1,3-dioxan-4,6-dione intermediate. For example, in a first reaction vessel a suitable 1,3-dioxan-4,6-dione is reacted with sufficient base to form a 1,3-dioxan-4,6-dione anion. This can be accomplished by first charging a dry reaction vessel with an equivalent of a base such as sodium hydride in a suitable solvent such as tetrahydrofuran (THF). In a second reaction vessel a suitable 1,3-dioxan-4,6-dione is dissolved in a suitable solvent, for example, 2,2-dimethyl-1,3-dioxan-4,6-dione in a sufficient amount of dry THF Next the contents of the second reaction vessel is added to the contents of the first reaction vessel while cooling the admixture. Once the 1,3-dioxan-4,6-dione anion is sufficiently formed, in a third reaction vessel, an activated acyl unit is dissolve in a sufficient amount of solvent, for example, 2-naphthoyl chloride, is dissolved in THF, and this solution is subsequently added to the solution of 1,3-dioxan-4,6-dione anion.
However, in other embodiments of the present invention, it may be necessary to warm the admixture of base, suitable 1,3-dioxan-4,6-dione, and solvent in a reaction vessel in order to fully generate the 1,3-dioxan-4,6-dione anion prior to addition of the activated acyl unit.
Also included in Step (a) of the present invention is neutralization of any remaining base prior to proceeding to Steps (b) or (c). In a preferred embodiment of the present process, Step (a) is conducted under an inert atmosphere.
Step (b) Optionally Isolating the 2-acyl-1,3-dioxan-4,6-dione formed in Step (a).
The formulator may choose to optionally isolate the 2-acyl-1,3-dioxan-4,6-dione form in Step (a) of the process of the present invention. Isolation may include, distillation, crystallization, chromatography and the like. However, it is not necessary that the intermediate 2-acyl-1,3-dioxan-4,6-dione be isolated prior to Step (c).
Step (c): Reacting the acyl 1,3-dioxane-4,6-dione formed in Step (a) or alternatively isolated in Step (b) with a fragrance raw material alcohol
The 2-acyl-1,3-dioxan-4,6-dione form in Step (a) is then reacted with a fragrance raw material alcohol to form a xcex2-ketoester having the formula: 
wherein xe2x80x94OR represents a unit derived form a fragrance raw material alcohol an dR3, R4, and R5 are the same as define herein above.
For the purposes of the present invention xe2x80x9cfragrance raw material alcoholsxe2x80x9d are herein defined as alcohols having a molecular weight and which are useful in imparting an odor, fragrance, essence, or scent either alone or in combination with other xe2x80x9cfragrance raw material alcoholsxe2x80x9d.
Non-limiting examples of preferred fragrance raw material alcohols include 2,4-dimethyl-3-cyclohexene-1-methanol (Floralol), 2,4-dimethyl cyclohexane methanol (Dihydro floralol), 5,6-dimethyl-1-methylethenylbicyclo[2.2.1]hept-5-ene-2-methanol (Arbozol), xcex1,xcex1,-4-trimethyl-3-cyclohexen-1-methanol (xcex1-terpineol), 2,4,6-trimethyl-3-cyclohexene-1-methanol (Isocyclo geraniol), 4-(1-methylethyl)cyclohexane methanol (Mayol), xcex1-3,3-trimethyl-2-norborane methanol, 1,1-dimethyl-1-(4-methylcyclohex-3-enyl)methanol, 2-phenylethanol, 2-cyclohexyl ethanol, 2-(o-methylphenyl)-ethanol, 2-(m-methylphenyl)ethanol, 2-(p-methylphenyl)ethanol, 6,6-dimethylbicyclo-[3.1.1]hept-2-ene-2-ethanol (nopol), 2-(4-methylphenoxy)-ethanol, 3,3-dimethyl-xcex942-xcex2-norbomane ethanol (patchomint), 2-methyl-2-cyclohexylethanol, 1-(4-isopropylcyclohexyl)-ethanol, 1-phenylethanol, 1,1-dimethyl-2-phenylethanol, 1,1-dimethyl-2-(4-methyl-phenyl)ethanol, 1-phenylpropanol, 3-phenylpropanol, 2-phenylpropanol (Hydrotropic Alcohol), 2-(cyclododecyl)propan-1-ol (Hydroxy-ambran), 2,2-dimethyl-3-(3-methylphenyl)-propan-1-ol (Majantol), 2-methyl-3-phenylpropanol, 3-phenyl-2-propen-1-ol (cinnamyl alcohol), 2-methyl-3-phenyl-2-propen-1-ol (methylcinnamyl alcohol), xcex1-n-pentyl-3-phenyl-2-propen-1-ol (xcex1-amyl-cinnamyl alcohol), ethyl-3-hydroxy-3-phenyl propionate, 2-(4-methylphenyl)-2-propanol, 3-(4-methylcyclohex-3-ene)butanol, 2-methyl-4-(2,2,3-trimethyl-3-cyclopenten-1-yl)butanol, 2-ethyl-4-(2,2,3-trimethyl-cyclopent-3-enyl)-2-buten-1-ol, 3-methyl-2-buten-1-ol (prenol), 2-methyl-4-(2,2,3-trimethyl-3-cyclopenten-1-yl)-2-buten-1-ol, ethyl 3-hydroxybutyrate, 4-phenyl-3-buten-2-ol, 2-methyl-4-phenylbutan-2-ol, 4-(4-hydroxyphenyl)butan-2-one, 4-(4-hydroxy-3-methoxyphenyl)-butan-2-one, 3-methyl-pentanol, 3-methyl-3-penten-1-ol, 1-(2-propenyl)cyclopentan-1-ol (plinol), 2-methyl-4-phenylpentanol (Pamplefleur), 3-methyl-5-phenylpentanol (Phenoxanol), 2-methyl-5-phenylpentanol, 2-methyl-5-(2,3-dimethyltricyclo[2.2.1.0(2,6)]hept-3-yl)-2-penten-1-ol (santalol), 4-methyl-1-phenyl-2-pentanol, 5-(2,2,3-trimethyl-3-cyclopentenyl)-3-methylpentan-2-ol (sandalore), (1-methyl-bicyclo[2.1.1]hepten-2-yl)-2-methylpent-1-en-3-ol, 3-methyl-1-phenylpentan-3-ol, 1,2-dimethyl-3-(1-methylethenyl)cyclopentan-1-ol, 2-isopropyl-5-methyl-2-hexenol, cis-3-hexen-1-ol, trans-2-hexen-1-ol, 2-isoproenyl-4-methyl-4-hexen-1-ol (Lavandulol), 2-ethyl-2-prenyl-3-hexenol, 1-hydroxymethyl-4-isopropenyl-1-cyclohexene (Dihydrocuminyl alcohol), 1-methyl-4-isopropenylcyclohex-6-en-2-ol (carvenol), 6-methyl-3-isopropenylcyclohexan-1-ol (dihydrocarveol), 1-methyl-4-iso-propenylcyclohexan-3-ol, 4-isopropyl-1-methylcyclohexan-3-ol, 4-tert-butylcyclo-hexanol, 2-tert-butylcyclohexanol, 2-tert-butyl-4-methylcyclohexanol (rootanol), 4-isopropyl-cyclohexanol, 4-methyl-1-(1-methylethyl)-3-cyclohexen-1-ol, 2-(5,6,6-trimethyl-2-norbornyl)cyclohexanol, isobomylcyclohexanol, 3,3,5-trimethylcyclohexanol, 1-methyl-4-isopropylcyclohexan-3-ol, 1-methyl-4-isopropylcyclohexan-8-ol (dihydroterpineol), 1,2-dimethyl-3-(1-methylethyl)cyclohexan-1-ol, heptanol, 2,4-dimethylheptan-1-ol, 6-heptyl-5-hepten-2-ol (isolinalool), 2,4-dimethyl-2,6-heptandienol, 6,6-dimethyl-2-oxymethyl-bicyclo[3.1.1]hept-2-ene (myrtenol), 4-methyl-2,4-heptadien-1-ol, 3,4,5,6,6-pentamethyl-2-heptanol, 3,6-dimethyl-3-vinyl-5-hepten-2-ol, 6,6-dimethyl-3-hydroxy-2-methylenebicyclo[3.1.1]heptane, 1,7,7-trimethylbicyclo[2.2.1]heptan-2-ol, 2,6-dimethylheptan-2-ol (dimetol), 2,6,6-trimethylbicyclo[1.3.3]heptan-2-ol, octanol, 2-octenol, 2-methyloctan-2-ol, 2-methyl-6-methylene-7-octen-2-ol (myrcenol), 7-methyloctan-1-ol, 3,7-dimethyl-6-octenol, 3,7-dimethyl-7-octenol, 3,7-dimethyl-6-octen-1-ol (citronellol), 3,7-dimethyl-2,6-octadien-1-ol (geraniol), 3,7-dimethyl-2,6-octadien-1-ol (nerol), 3,7-dimethyl-7-methoxyoctan-2-ol (osyrol), 3,7-dimethyl-1,6-octadien-3-ol (linalool), 3,7-dimethyloctan-1-ol (pelargol), 3,7-dimethyloctan-3-ol (tetrahydrolinalool), 2,4-octadien-1-ol, 3,7-dimethyl-6-octen-3-ol (dihydrolinalool), 2,6-dimethyl-7-octen-2-ol (dihydromyrcenol), 2,6-dimethyl-5,7-octadien-2-ol, 4,7-dimethyl-4-vinyl-6-octen-3-ol, 3-methyloctan-3-ol, 2,6-dimethyloctan-2-ol, 2,6-dimethyloctan-3-ol, 3,6-dimethyloctan-3-ol, 2,6-dimethyl-7-octen-2-ol, 2,6-dimethyl-3,5-octadien-2-ol (muguol), 3-methyl-1-octen-3-ol, 7-hydroxy-3,7-dimethyloctanal, 3-nonanol, 2,6-nonadien-1-ol, cis-6-nonen-1-ol, 6,8-dimethylnonan-2-ol, 3-(hydroxymethyl)-2-nonanone, 2-nonen-1-ol, 2,4-nonadien-1-ol, 3,7-dimethyl-1,6-nonadien-3-ol, decanol, 9-decenol, 2-benzyl-M-dioxa-5-ol, 2-decen-1-ol, 2,4-decadien-1-ol, 4-methyl-3-decen-5-ol, 3,7,9-trimethyl-1,6-decadien-3-ol (isobutyl linalool), undecanol, 2-undecen-1-ol, 10-undecen-1-ol, 2-dodecen-1-ol, 2,4-dodecadien-1-ol, 2,7,11-trimethyl-2,6,10-dodecatrien-1-ol (farnesol), 3,7,11-trimethyl-1,6,10,-dodecatrien-3-ol (nerolidol), 3,7,11,15-tetramethylhexadec-2-en-1-ol (phytol), 3,7,11,15-tetramethylhexadec-1-en-3-ol (iso phytol), benzyl alcohol, p-methoxy benzyl alcohol (anisyl alcohol), para-cymen-7-ol (cuminyl alcohol), 4-methyl benzyl alcohol, 3,4-methylenedioxy benzyl alcohol, methyl salicylate, benzyl salicylate, cis-3-hexenyl salicylate, n-pentyl salicylate, 2-phenylethyl salicylate, n-hexyl salicylate, 2-methyl-5-isopropylphenol, 4-ethyl-2-methoxyphenol, 4-allyl-2-methoxyphenol (eugenol), 2-methoxy-4-(1-propenyl)phenol (isoeugenol), 4-allyl-2,6-dimethoxy-phenol, 4-tert-butylphenol, 2-ethoxy-4-methylphenol, 2-methyl-4-vinylphenol, 2-isopropyl-5-methylphenol (thymol), pentyl-ortho-hydroxy benzoate, ethyl 2-hydroxy-benzoate, methyl 2,4-dihydroxy-3,6-dimethylbenzoate, 3-hydroxy-5-methoxy-1-methylbenzene, 2-tert-butyl-4-methyl-1-hydroxybenzene, 1-ethoxy-2-hydroxy-4-propenylbenzene, 4-hydroxytoluene, 4-hydroxy-3-methoxybenzaldehyde, 2-ethoxy-4-hydroxybenzaldehyde, decahydro-2-naphthol, 2,5,5-trimethyl-octahydro-2-naphthol, 1,3,3-trimethyl-2-norbornanol (fenchol), 3a,4,5,6,7,7a-hexahydro-2,4-dimethyl-4,7-methano-1H-inden-5-ol, 3a,4,5,6,7,7a-hexahydro-3,4-dimethyl-4,7-methano-1H-inden-5-ol, 2-methyl-2-vinyl-5-(1-hydroxy-1-methylethyl)tetrahydrofuran, xcex2-caryophyllene alcohol, vanillin, ethyl vanillin, and mixtures thereof.
More preferably, the fragrance raw material alcohol is selected from the group consisting of cis-3-hexen-1-ol, hawthanol [admixture of 2-(o-methylphenyl)ethanol, 2-(m-methylphenyl)ethanol, and 2-(p-methylphenyl)ethanol], heptan-1-ol, decan-1-ol, 2,4-dimethyl cyclohexane methanol, 4-methylbutan-1-ol, 2,4,6-trimethyl-3-cyclohexene-1-methanol, 4-(1-methylethyl)cyclohexane methanol, 3-(hydroxy-methyl)-2-nonanone, octan-1-ol, 3-phenylpropanol, Rhodinol 70 [3,7-dimethyl-7-octenol, 3,7-dimethyl-6-octenol admixture], 9-decen-1-ol, xcex1-3,3-trimethyl-2-norborane methanol, 3-cyclohexylpropan-1-ol, 4-methyl-1-phenyl-2-pentanol, 3,6-dimethyl-3-vinyl-5-hepten-2-ol, phenyl ethyl methanol; propyl benzyl methanol, 1-methyl-4-isopropenylcyclohexan-3-ol, 4-isopropyl-1-methylcyclohexan-3-ol (menthol), 4-tert-butylcyclohexanol, 2-tert-butyl-4-methylcyclohexanol, 4-isopropylcyclo-hexanol, trans-decahydro-xcex2-naphthol, 2-tert-butylcyclohexanol, 3-phenyl-2-propen-1-ol, 2,7,11-trimethyl-2,6,10-dodecatrien-1-ol, 3,7-dimethyl-2,6-octadien-1-ol (geraniol), 3,7-dimethyl-2,6-octadien-1-ol (nerol), 4-methoxybenzyl alcohol, benzyl alcohol, 4-allyl-2-methoxyphenol, 2-methoxy-4-(1-propenyl)phenol, vanillin, and mixtures thereof.
Step (c) of the present process can be conducted in the presence of a suitable solvent or an excess amount of the fragrance raw material alcohol may be used as a solvent. Non-limiting examples of suitable solvents include dichloromethane, 1,2-dichloroethane, 1,2,3-trichloroethane, pentane, hexane, tetrahydrofuran, diethyl ether, benzene, toluene, xylene, 1,4-dioxane, acetonitrile, N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), hexamethyl phosphoramide (HMPA), and mixtures thereof.
The reaction of Step (c) may be successfully conducted, depending upon the reactivity of the reagents, the scope of the reaction, and other mitigating parameters, at a temperature of from about 0xc2x0 C., preferably from about 22xc2x0 C. (approximately room temperature), more preferably from about 40xc2x0 C., to about 200xc2x0 C., preferably to about 150xc2x0 C., more preferably to about 100xc2x0 C., most preferably to about 80xc2x0 C.
Included in Step (c) of the present invention is a provision for neutralizing any base present from Step (a) above. In a preferred embodiment of the present process, Step (c) is conducted under an inert atmosphere. In addition, an amount of a suitable acid catalyst may be added to the reaction of Step (c).
The product thus obtained from Step (c) of the present process can be purified by any conventional means depending upon the form physical form of the obtained xcex2-ketoester. Non-limiting examples include chromatography, crystalizedion, distillation, sublimation, etc.